Vibro-acoustic system

ABSTRACT

The present invention is directed to providing a vibro-acoustic system that can be used for an extended period of time by reducing the uncomfortable feeling or sensation of pressure that a user may experience during use. The vibro-acoustic system comprises: a seat having a seatback and a seat proper; a band dividing circuit which produces a first sound signal and a second sound signal by dividing an input sound signal into frequency bands; a first vibrating device which vibrates in accordance with the first sound signal, and which is mounted in the seatback so that the direction of vibration of the first vibrating device is parallel or substantially parallel to the occupant-side surface of the seatback; and a second vibrating device which vibrates In accordance with the second sound signal, and which is mounted in the seat proper so that the direction of vibration of the second vibrating device is parallel or substantially parallel to the occupant-side surface of the seat proper.

This application is a new U.S. patent application that claims benefit ofJP 2006-325606, filed on Dec. 1, 2006, the entire content of JP2006-325606 is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a vibro-acoustic system, or morespecifically to a vibro-acoustic system for mounting in a vehicle seat.

BACKGROUND ART

A vibro-acoustic system generally known as “Bodysonic” comprises a meansfor providing physically perceptible vibrations and a speaker bothmounted in a chair, a cushion, or the like, and a user can easilyexperience a dynamic sensation and realistic feeling playbacked sounds.

An apparatus is known in which such a vibro-acoustic system is used in avehicle seat (for example, refer to patent document 1). In the systemdescribed in patent document 1, a transducer is mounted on a structuralframe of the vehicle seat so that the vibration of the transducer istransmitted to the occupant of the seat via the frame.

However, with this apparatus, since the transducer vibrates in adirection directly opposed to the direction of the occupant, there hasbeen the problem that the occupant, when subjected to the vibrations foran extended period of time, may feel an unpleasant sensation and mayexperience, for example, an uncomfortable feeling or sensation ofpressure. This has presented a serious problem particularly in the caseof vehicle seats where the occupants have to stay seated for a longperiod of time.

Patent document 1: Japanese Utility Model Publication No. H06-23389(FIG. 1)

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide avibro-acoustic system that can solve the above problem.

It is another object of the present invention to provide avibro-acoustic system that can be used for an extended period of time byreducing an uncomfortable feeling or sensation of pressure that the usermay experience during use.

A vibro-acoustic system according to the present invention comprises: aseat having a seatback and a seat proper; and a vibrating device whichvibrates in accordance with an applied sound signal, wherein thevibrating device is mounted in the seat so that the direction ofvibration of the vibrating device is parallel or substantially parallelto the occupant-side surface of the seatback or the seat proper.

Further, a vibro-acoustic system according to the present inventioncomprises: a seat having a seatback and a seat proper; a band dividingcircuit which produces a first sound signal and a second sound signal bydividing an input sound signal into frequency bands; a first vibratingdevice which vibrates in accordance with the first sound signal, andwhich is mounted in the seatback so that the direction of vibration ofthe first vibrating device is parallel or substantially parallel to theoccupant-side surface of the seatback; and a second vibrating devicewhich vibrates in accordance with the second sound signal, and which ismounted in the seat proper so that the direction of vibration of thesecond vibrating device is parallel or substantially parallel to theoccupant-side surface of the seat proper.

Preferably, the vibro-acoustic system according to the present inventionfurther comprises a source which produces the sound signal.

According to the vibro-acoustic system of the present invention, sinceeach vibrating device that vibrates is mounted so that the direction ofits vibration is not perpendicular to the occupant-side surface of theseatback or the seat proper, i.e., the direction of vibration isparallel or substantially parallel to the surface, the system can beused for an extended period of time without causing very much discomfortor sensation of pressure to the occupant.

Furthermore, according to the vibro-acoustic system of the presentinvention, since the sound signal from the source is divided intofrequency bands, and the vibrating devices mounted separately in theseat are driven independently of each other, more dynamic and realisticsensations can be provided to the user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1( a) is a diagram explaining the operation of a vibro-acousticsystem according to the present invention, and FIG. 1( b) is a diagramexplaining the operation of a vibro-acoustic system according the priorart.

FIG. 2 is a block diagram showing the general configuration of thevibro-acoustic system 100 according to the present invention.

FIG. 3 is a diagram showing an example in which vibrating devices aremounted in a vehicle seat.

FIG. 4 is a diagram showing the arrangement of the vibrating devices asviewed from the back of the vehicle seat.

FIG. 5 is a diagram showing another mounting example of the vibratingdevices.

FIG. 6 is a diagram showing still another mounting example of thevibrating devices.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vibro-acoustic system according to the present invention will bedescribed below with reference to the drawings. However, it should benoted that the scope of the present invention is not limited by thespecific embodiments described herein, but may be defined by theappended claims and their equivalents.

FIG. 1 is a diagram explaining the operation of the vibro-acousticsystem according to the present invention.

FIG. 1( a) shows an example in which a vibrating device 1 used in thevibro-acoustic system of the present invention is mounted in a seat 10,while FIG. 1( b) shows an example in which a conventional Bodysonic-typetransducer 2 and a vibrating plate 3 are mounted in the seat 10. Here,seat 10 comprises a headrest 11, a seatback 12, and a seat proper 13.

Unlike conventional transducer 2, vibrating device 1 contains a vibratorthat has an increased thickness and a cylindrical shape and thatvibrates in a direction parallel to the longitudinal direction of thevibrating device. The vibrator is designed so that the intensity of itsvibration varies in accordance with the sound signal applied to thevibrating device 1. Accordingly, when a sound signal is applied to thevibrating device 1, the vibrating device vibrates in accordance with theapplied sound signal.

In FIG. 1( a), the vibrating device 1 is mounted vertically in theseatback 12 of the seat 10. When a sound signal is applied to thevibrating device 1, the vibrating device 1 vibrates in the directionindicated by arrow A shown in FIG. 1( a); as a result, the vibrationpropagates along the vertical direction of the seatback 12, causing theentire structure of the seatback 12 to vibrate, and the resultingvibration is transmitted to the occupant of the seat 10. In other words,the vibrating device 1 is mounted so that the direction of its vibrationis not perpendicular to the occupant-side surface of the seatback 12,i.e., the direction of vibration is parallel or substantially parallelto the surface. Accordingly, the occupant can feel very soft vibrations,and even when the occupant stays seated for an extended period of timein the seat 10 equipped with the vibrating device 1, the occupant doesnot experience an uncomfortable feeling or a sensation of pressure.

In FIG. 1( b), the transducer 2 causes the vibrating plate 3 to vibrate,and the vibration of the vibrating plate 3 directly strikes theoccupant's back; this structure can easily produce strong vibrations,but when subjected to vibrations for an extended period of time, theoccupant may have an uncomfortable feeling or a sensation of pressure.In other words, the conventional transducer 2 is mounted so that thedirection of its vibration (the direction indicated by arrow B) isperpendicular to the occupant-side surface of the seatback 12.

In this way, according to the vibro-acoustic system of the presentinvention, since the vibrating device 1 is mounted so that the directionof its vibration is not perpendicular to the occupant-side surface ofthe seatback 12 (or the seat proper 13) but is parallel or substantiallyparallel to the surface, the vibrations do not directly strike theoccupant's back, and the occupant does not experience an uncomfortablefeeling or a sensation of pressure even when the occupant stays seatedfor an extended period of time.

FIG. 2 is a block diagram showing the general configuration of thevibro-acoustic system 100 according to the present invention.

The vibro-acoustic system 100 comprises a source 110, a waveformextracting circuit 120, an FFT circuit 130, a band dividing circuit 140,an amplifying unit 150, and vibrating devices 160 to 169.

The source 110 which produces a sound signal may be one or a pluralityof sources selected from among a CD/MD playback unit, a radio receiverunit, a TV receiver unit, a DVD playback unit, an HD (Hard Disk)playback unit, and a navigation unit.

The waveform extracting circuit 120 extracts the waveform of the soundsignal output from the source 110, the FFT circuit 130 extracts thesound signal for each frequency band, and the band dividing circuit 140divides the sound signal into three predetermined bands, i.e., the firstmid-to-low frequency band (150 to 200 Hz), the second mid-to-lowfrequency band (100 to 150 Hz), and the low frequency band (50 to 100Hz), for output to the amplifier circuit 150.

The band dividing circuit 140 distributes the sound signal in the firstmid-to-low frequency band (150 to 200 Hz) to a first vibrating devicegroup consisting of the vibrating devices 160 and 161, the sound signalin the second mid-to-low frequency band (100 to 150 Hz) to a secondvibrating device group consisting of the vibrating devices 162 and 163,and the sound signal in the low frequency band (50 to 100 Hz) to a thirdvibrating device group consisting of the vibrating devices 164 to 169.Each of the vibrating devices 160 to 169 used here is identical to thevibrating device 1 described with reference to FIG. 1( a).

The amplifier circuit 150, which is paired with the vibrating devices160 to 169, amplifies the sound signals output from the band dividingcircuit 140 and outputs them to the respective vibrating devices.

Though not shown in FIG. 2, the vibro-acoustic system 100 includes aplurality of speakers for reproducing sound signals higher than thefirst mid-to-low frequency band signal (150 to 200 Hz). It will also benoted that the vibro-acoustic system 100 need not necessarily includethe source 110 and/or the vibrating devices 160 to 169.

FIG. 3 is a diagram showing an example in which the vibrating devicesare mounted in a vehicle seat.

As shown in FIG. 3, the vibrating devices 160 and 161 of the firstvibrating device group are mounted in the upper half of the seatback 12at positions spaced apart from the centerline A of the seatback 12, thevibrating devices 162 and 163 of the second vibrating device group aremounted in the lower half of the seatback 12 at positions spaced apartfrom the centerline A of the seatback 12, the vibrating devices 164 to167 of the third vibrating device group are mounted in the seat proper13 at positions spaced apart from the centerline A of the seat proper13, and the vibrating devices 168 and 169 of the third vibrating devicegroup are mounted in the forward end portion of the seat proper 13. Allof the vibrating devices are mounted by avoiding the positions where theoccupant's back or buttocks directly contact the seatback 12 or the seatproper 13 when the occupant is seated in the seat 10.

FIG. 4 is a diagram showing the arrangement of the vibrating devices asviewed from the back of the vehicle seat.

As shown in FIG. 4, the vibrating devices 160 to 163 are mounted so asto be embedded in a polyurethane foam 15 which is a seat materialsupported by such means as springs and the seat frame 14 of the seat 10.Preferably, the vibrating devices are mounted by first forming recesseseach slightly smaller than each vibrating device in the polyurethanefoam 15 and then pushing the vibrating devices into the respectiverecesses in the polyurethane foam, because the vibrations from thevibrating devices can then be transmitted effectively to the seat. Sincethe recent trend is to reduce the thickness of the vehicle seat 10,embedding the vibrating devices in polyurethane foam is also preferablefrom the standpoint of securing space for mounting the vibratingdevices.

The hardness of the polyurethane form is in the range of 10 to 350 N,which is sufficient to transmit the vibrations of the vibrating devices.Here, either rigid urethane or soft urethane may be used as long as itis foamed urethane.

Though not shown in FIG. 4, the vibrating devices 164 to 169 mounted inthe seat proper 13 are likewise embedded in the polyurethane foam of theseat proper 13.

Next, the operation of the vibro-acoustic system 100 will be described.

Referring to the configuration shown in FIG. 2, the sound signal inputfrom the source 110 is divided into three frequency bands, the firstmid-to-low frequency band (150 to 200 Hz), the second mid-to-lowfrequency band (100 to 150 Hz), and the low frequency band (50 to 100Hz), and the sound signals of the respective frequency bands aredistributed to the first to third vibrating device groups, respectively.The vibrating devices of the first to third vibrating device groupsvibrate in accordance with the applied sound signals, and vibrationsproviding a dynamic sensation and a realistic feeling can thus betransmitted to the occupant of the seat 10. As earlier described, all ofthe vibrating devices 160 to 169 are mounted by avoiding positions wherethe occupant's back or buttocks directly contact the seatback 12 or theseat proper 13 when the occupant is seated in the seat 10. As a result,the vibrations can be transmitted indirectly to the occupant, reducingthe possibility of giving the occupant an uncomfortable feeling or asensation of pressure even when the system is used for an extendedperiod of time.

The reason that the vibrating devices corresponding to the firstmid-to-low frequency band (150 to 200 Hz) are mounted in the upper halfof the seatback 12 while the vibrating devices corresponding to the lowfrequency band (50 to 100 Hz) are mounted in the seat proper 13 is thatthe human body is sensitive to low-frequency vibrations applied fromunder the body.

In the above description, it should be noted that the number and thearrangement of the vibrating devices and the classification of the firstmid-to-low frequency band, the second mid-to-low frequency band, and thelow frequency band are only examples and may be changed appropriately tosuit the shape and material of the seat, the shape of the vehiclecompartment, etc.

Further, in the above description, three sound signals have been createdby dividing the sound signal from the source 110 into three frequencybands, and the vibrating devices of the first to third vibrating devicegroups have been caused to vibrate simultaneously in accordance with therespective sound signals. Alternatively, control may be performed sothat when the sound signal from the source 110 is rich in frequencycomponents falling within the first mid-to-low frequency band (150 to200 Hz), only the vibrating devices 160 and 161 of the first vibratingdevice group are caused to vibrate, but when the sound signal is rich infrequency components falling within the second mid-to-low frequency band(100 to 150 Hz), only the vibrating devices 162 and 163 of the secondvibrating device group are caused to vibrate, while on the other hand,when the sound signal is rich in frequency components falling within thelow frequency band (50 to 100 Hz), only the vibrating devices 164 to 169of the third vibrating device group are caused to vibrate. Control forthe above mode switching is performed by the band dividing circuit 40.

Further, a selector switch for allowing the occupant to select which ofthe first to third vibrating device groups is to be caused to vibratemay be provided on or near the seat 10 so that the mode switching by theband dividing circuit 40 can be controlled in accordance with thesetting of the selector switch.

FIG. 5 is a diagram showing another mounting example of the vibratingdevices.

In the example of FIG. 5, two vibrating devices 170 and 171 are mountedonly in the center portion of the seatback 12 of the seat 10 byarranging the vibrating devices along a direction perpendicular to thelongitudinal direction of the seatback 12. In this case also, thevibrating devices 170 and 171 are mounted to avoid positions thatdirectly contact the occupant's back when the occupant is seated in theseat 10. Further, since each of the vibrating devices 170 and 171 ismounted so that the direction of its vibration is parallel orsubstantially parallel to the occupant-side surface of the seatback 12,the vibration can be transmitted indirectly to the occupant, reducingthe possibility of giving the occupant an uncomfortable feeling or asensation of pressure even when the system is used for an extendedperiod of time.

In the case of FIG. 5, the vibrating devices 170 and 171 are driven bythe sound signal representing the entire frequency range (200 to 50 Hz)

FIG. 6 is a diagram showing still another mounting example of thevibrating devices.

In the example of FIG. 6, two vibrating devices 180 and 181 are mountedonly in the center portion of the seatback of the seat 10 by arrangingthe vibrating devices along a direction parallel to the longitudinaldirection of the seatback 12. In this case, the vibrating devices 180and 181 are mounted to avoid positions that directly contact theoccupant's back when the occupant is seated in the seat 10. Further,since each of the vibrating devices 180 and 181 is mounted so that thedirection of its vibration is parallel or substantially parallel to theoccupant-side surface of the seatback 12, the vibration can betransmitted indirectly to the occupant, reducing the possibility ofgiving the occupant an uncomfortable feeling or a sensation of pressureeven when the system is used for an extended period of time.

In the case of FIG. 6, the vibrating devices 180 and 181 are driven bythe sound signal representing the entire frequency range (200 to 50 Hz).

1. A vibro-acoustic system comprising: a seat having a seatback and aseat proper; and a vibrating device which vibrates in accordance with anapplied sound signal, wherein said vibrating device is mounted in saidseat so that the direction of vibration of said vibrating device isparallel or substantially parallel to an occupant-side surface of saidseatback or said seat proper.
 2. The vibro-acoustic system according toclaim 1, further comprising a source which produces said sound signal.3. A vibro-acoustic system comprising: a seat having a seatback and aseat proper; a band dividing circuit which produces a first sound signaland a second sound signal by dividing an input sound signal intofrequency bands; a first vibrating device which vibrates in accordancewith said first sound signal, and which is mounted in said seatback sothat the direction of vibration of said first vibrating device isparallel or substantially parallel to an occupant-side surface of saidseatback; and a second vibrating device which vibrates in accordancewith said second sound signal, and which is mounted in said seat properso that the direction of vibration of said second vibrating device isparallel or substantially parallel to an occupant-side surface of saidseat proper.
 4. The vibro-acoustic system according to claim 3, furthercomprising a source which produces said sound signal.
 5. Thevibro-acoustic system according to claim 3, wherein said first soundsignal is higher in frequency than said second sound signal.
 6. Thevibro-acoustic system according to claim 3, wherein said seatback andsaid seat proper are each formed from a polyurethane foam, and saidfirst and second vibrating devices are mounted so as to be embedded inthe respective polyurethane foams.
 7. The vibro-acoustic systemaccording to claim 3, further comprising a selecting means for selectingwhich of the first and second vibrating devices is to be caused tovibrate.